Mounting it inside your hull will give you a good idea of the temperature inside the hull.

The transducer doesn't "shoot" for temperature: there is a thermometer inside the transducer, so the measurement you see is the temperature of the transducer itself. If it's not in the water, you don't get water temperatures.

I have read that it will give a measurement although not accurate. I can't get any measurement. Just a blinking 32 which is the default. I assumed I would get some measurement that would be something higher than the actual water temp.

Hate to say this, but this seems to be a common problem with Lowrance units....I had my LMS-240 in for repair twice under warranty.....they were repaired and then failed again ....I finally gave up on the temperature function.

KHG....my reply was with a Lowrance transducer unit mounted on the stern of my 18' Jetcraft and I experienced the exact same temperature fault reported.You can reset the unit and it still will not work properly.....as in defective.....just say'n

On the other hand, my Humminbird 768 will indicate the water temperature, thru the hull of my Outback with only a 2 degree error/difference after 30 minutes in the water using a good thermometer directly in the water.

Cool, didn't see any mention of your setup in the thread before now...

Nice that Humminbird programs their system to do that. I'd be guessing that Lowrance doesn't as it isn't something they expected to have people do with their transducers... As explained in their tech support reply.